Gypsum
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| Gypsum[1][2] | |
| |
| Mineralogical name | Gypsum, Selenite |
| Chemical name | Calcium sulfate dihydrate |
| Trivial name | Gypsite, Sulfate of Lime |
| Chemical formula | Ca[SO4]•2H2O |
| Other forms | Anhydrite (CaSO4) Hemihydrate (CaSO4•0.5H2O) |
| Crystal system | monoclinic |
| Crystal structure | |
| Deliquescence humidity 20°C | |
| Solubility (g/l) at 20°C | 2.14 g/l |
| Density (g/cm³) | 2.2-2.4 g/cm³ |
| Molar volume | 74.69 cm3/mol |
| Molar weight | 172.17g /mol |
| Transparency | transparent to opaque |
| Cleavage | perfect |
| Crystal habit | |
| Twinning | |
| Phase transition | |
| Chemical behavior | |
| Comments | hardly soluble in water |
| Crystal Optics | |
| Refractive Indices | α = 1.519-1.521 β = 1.522-1.523 γ = 1.529-1.530 |
| Birefringence | Δ = 0.010 |
| Optical Orientation | biaxial positive |
| Pleochroism | |
| Dispersion | 58° |
| Used Literature | |
| {{{Literature}}} | |
back to Sulfate
Weblinks[edit]
- ↑ http://webmineral.com/data/Gypsum.shtml seen on 30.07.2010
- ↑ http://www.mindat.org/min-1784.html seen on 30.07.2010